Ascomycin, also called Immunomycin, FR-900520, FK520, is an
ethyl analog of
tacrolimus
Tacrolimus, sold under the brand name Prograf among others, is an immunosuppressive drug. After allogeneic organ transplant, the risk of organ rejection is moderate. To lower the risk of organ rejection, tacrolimus is given. The drug can also ...
(FK506) with strong immunosuppressant properties. It has been researched for the treatment of
autoimmune diseases and
skin diseases
A skin condition, also known as cutaneous condition, is any medical condition that affects the integumentary system—the organ system that encloses the body and includes skin, nails, and related muscle and glands. The major function of thi ...
, and to prevent rejection after an
organ transplant
Organ transplantation is a medical procedure in which an organ (anatomy), organ is removed from one body and placed in the body of a recipient, to replace a damaged or missing organ. The donor and recipient may be at the same location, or organ ...
.
Ascomycin acts by binding to
immunophilins
In molecular biology, immunophilins are endogenous cytosolic peptidyl-prolyl isomerases (PPI) that catalyze the interconversion between the cis and trans isomers of peptide bonds containing the amino acid proline (Pro). They are chaperone molecul ...
, especially
macrophilin-12. It appears that Ascomycin inhibits the production of Th1 (interferon- and IL-2) and Th2 (IL-4 and IL-10)
cytokine
Cytokines are a broad and loose category of small proteins (~5–25 kDa) important in cell signaling. Cytokines are peptides and cannot cross the lipid bilayer of cells to enter the cytoplasm. Cytokines have been shown to be involved in autocrin ...
s. Additionally, ascomycin preferentially inhibits the activation of
mast cells
A mast cell (also known as a mastocyte or a labrocyte) is a resident cell of connective tissue that contains many granules rich in histamine and heparin. Specifically, it is a type of granulocyte derived from the myeloid stem cell that is a ...
, an important cellular component of the atopic response. Ascomycin produces a more selective
immunomodulatory
Immunotherapy or biological therapy is the treatment of disease by activating or suppressing the immune system. Immunotherapies designed to elicit or amplify an immune response are classified as ''activation immunotherapies,'' while immunotherap ...
effect in that it inhibits the elicitation phase of
allergic contact dermatitis
Allergic contact dermatitis (ACD) is a form of contact dermatitis that is the manifestation of an allergic response caused by contact with a substance; the other type being irritant contact dermatitis (ICD).
Although less common than ICD, ACD is ...
but does not impair the primary immune response when administered systemically.
Ascomycin is produced by the
fermentation of certain strains of ''
Streptomyces hygroscopicus''.
In fiction
Ascomycin is also the name of a fictional "antiagathic" (anti-aging) drug in
James Blish
James Benjamin Blish () was an American science fiction and fantasy writer. He is best known for his '' Cities in Flight'' novels and his series of ''Star Trek'' novelizations written with his wife, J. A. Lawrence. His novel '' A Case of Conscie ...
's future history ''
Cities in Flight
''Cities in Flight'' is a four-volume series of science fiction novels and short stories by American writer James Blish, originally published between 1950 and 1962, which were first known collectively as the "Okie" novels. The series features ent ...
''.
and also They shall have stars.
Related compounds
Tacrolimus
Tacrolimus, sold under the brand name Prograf among others, is an immunosuppressive drug. After allogeneic organ transplant, the risk of organ rejection is moderate. To lower the risk of organ rejection, tacrolimus is given. The drug can also ...
,
Pimecrolimus
Pimecrolimus is an immunomodulating agent of the calcineurin inhibitor class used in the treatment of atopic dermatitis (eczema). It is available as a topical cream, once marketed by Novartis (however, Galderma has been promoting the compound i ...
References
Further reading
*
*
*
*
*
{{refend
External links
Exciting New Eczema Treatment Expected This YearBy Jane Schwanke, WebMD Medical News March 17, 2000 (San Francisco)
Immunosuppressants